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FX3G/FX3U/FX3UC Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
16 External FX Device – FNC 80 to FNC 89
16.9 FNC 88 – PID / PID Control Loop
16.9 FNC 88 – PID / PID Control Loop
Outline
This instruction executes PID control which changes the output value according to the input variation.
→ For details, refer to the Analog Control Edition.
1. Instruction format
2. Set data
3. Applicable devices
S: This function is supported only in FX3U/FX3UC PLCs.
Explanation of function and operation
1. 16-bit operation (PID)
When the target value , measured value , and parameters to +6 are set and a program is
executed, the operation result (MV) is stored to the output value at every sampling time .
Operand type Description Data type
Data register number storing the target value (SV) 16-bit binary
Data register number storing the measured value (PV) 16-bit binary
Data register number storing a parameter 16-bit binary
Data register number storing the output value (MV) 16-bit binary
Oper-
and
Type
Bit Devices Word Devices Others
System User Digit Specification System User
Special
Unit
Index
Con-
stant
Real
Number
Charac-
ter String
Pointer
XYMTCSD
.b KnX KnY KnM KnS T C D R
U\G
V Z Modify K H E "
"P
33 S
33 S
33
33 S
FNC 88
PID
−
Mnemonic Operation Condition
16-bit Instruction
9 steps PID
Mnemonic Operation Condition
Continuous
Operation
32-bit Instruction
S
1
S
1
S
1
S
2
S
3
S
1
D
S
1
S
1
S
1
S
2
S
2
S
3
S
1
D
S
1
S
2
S
3
S
3
D S
3
Command
input
FNC 88
PID
S
3
S
2
S
1
D
Target value (SV)
Measured value (PV)
Parameter
Output value (MV)